Laminated magnetic signboard

ABSTRACT

A signboard comprising a lightweight laminate incorporating a core of strong lightweight material such as polystyrene between a ferromagnetic sandwich sheet, with a suitable frame and lightweight magnetic symbols presented thereon. The lightweight magnetic symbols are fabricated from a strong lightweight material such as fiberglass or plastic, and are magnetically affixed to selected points on the ferromagnetic surface of the signboard by a magnetic sheet material on each symbol.

United States Patent McCormick et a1.

[ 1 Mar. 28, 1972 [541 LAMINATED MAGNETIC SIGNBOARD 221 Filed: May2l, 1970 [21] App1.No.: 39,417

[52] U.S.Cl. ..40/l42A [51] Int. Cl. ..G0917/02 [58] Fleldof Search ...40/142 A, 140, 125, 154, 152

. [56] References Cited UNITED STATES PATENTS 1,494,583 5/1924 Brooks ..40/125 F 2,254,498 9/1941 Scharf ..40/142 F 3,122,684 2/1964 Genin ..40/142 A X 3,226,838 1/1966 Courrege et a1 ..40/l42 A X 3,440,750 4/1969 Toth et al ..40/125 X 3,456,373 7/1969 Epton .40/142 A X 3,458,945 8/1969 Edwards ..40/ 140 Primary Examiner-Robert W. Michell Assistant Examiner-Wenceslao J. Contreras Attamey-George F. Bethel [5 7] ABSTRACT A signboard comprising a lightweight laminate incorporating a core of strong lightweight material such as polystyrene between a ferromagnetic sandwich sheet, with a suitable frame and lightweight magnetic symbols presented thereon. The lightweight magnetic symbols are fabricated from a strong lightweight material such as fiberglass or plastic, and are magnetically affixed to selected points on the ferromagnetic surface of the signboard by a magnetic sheet material on each symbol.

4 Claims, 6 Drawing Figures 14 r l2 I6 Patented Mmh 28, 1912 3,651,592

l4 l2 l6 20 I9 22 /P6 I2 l8 Vwa 1 e 5 FIG.6

INVENTOR. HAROLD H. McCORMICK B BOBERT F. SCHROEDER LAMINATED MAGNETIC SIGNBOARD BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is within the signboard art.

2. Description of the Prior Art A wide variety of signboards are commercially available at the present time. Traditionally large signboards have paper material glued to them. Other commercial signboards are designed so that removable symbols can be mechanically attached thereto. A wide variety of devices are-used to mechanically attach such symbols to signboards.

Among the foregoing are a variety of combinations utilizing a male protuberance on either the signboard or the symbol,

which mates with a corresponding female receptacle in the opposite member of the combination. Various types of slots for the receipt of appropriately designed hooks or protuberances are also widely used. Many of the slot combinations utilize a spring-like hook to enhance the connection between the symbol and the signboard. Other slots are designed so that the force of gravity causes the symbol to be held to the signboard. Some slots are designed so that the symbol can be removed by exerting a force in a pre-selected direction or combination of directions but cannot be removed by exerting forces in other than the pre-selected directions.

The prior art also describes signboards utilizing combinations of the above methods to affix symbols thereto. Unfortunately, the prior art does not disclose a lightweight signboard utilizing lightweight symbols wherein the signboard and the symbols present no dangerous corners or protuberances, and can be easily changed.

Lightness in signboard and symbol weight is important for certain applications. This is particularly true for those advertising applications wherein frequent changes of the contents or location of the sign are desirable. Hooks, slots, and the various protuberances and receptacles all present disadvantages, since they reduce the strength to weight ratio and total surface area of the signboard and attendant symbols. In addition to being more attractive and strong, relatively smooth surfaced signboards and symbols present important advantages in storage and safety.

An undesirable feature of the foregoing types of signboards has been the lack of ease and facility with which the sign can be changed. In other words, the removal and replacement of certain symbols forming the language of the signboard has been time consuming. Therefore, signs have often gone unchanged for want of time.

Magnetic coupling has been used to removably attach a wide variety of different items, but has never been successfully used for commercial signboards. Oneof the disadvantages of magnetic coupling for large signboards has been the large weight of the ferromagnetic structure which would have to make up the surface of a strong and stable signboard. F urthermore, if a ferromagnetic structure for a signboard were fabricated from a thin sheet to eliminate weight, it would tend' to collapse under its own weight or bend easily and not stand the required stresses over similarly long periods of time. Also, if the symbols were made entirely of a magnetic material, the weight of a large quantity of symbols'might cause a ferromagnetic signboard to collapse or bend.

SUMMARY OF THE INVENTION In summation, this invention is a signboard comprising a lightweight ferromagnetic surfaced laminate, having a suitable frame and lightweight magnetic symbols. The laminate comprises a supporting core and at least one ferromagnetic surface. The supporting core is fabricated from a material which cooperates with the surface to resist stress and strain, yet is very lightweight. Fiberglass, polystyrene, honeycomb core and other lightweight plastics and composites can form suitable cellular core materials.

The laminate is fabricated by coating or attachinga thin sheet of ferromagnetic material to at least one side of the core.

The ferromagnetic material may be deposited, sprayed on, glued on, or attached by any means known to the art, and, is preferably a thin sheet of steel. The structural strength of the composite is provided by the core and the layer of ferromagnetic material forming a composite with an extended central axis utilizing the strength principles of most lightweight cored laminates. The signboard of this invention can display a sign in either of two opposite directions, so that in most embodiments a layer of ferromagnetic material should be attached to each of two sides of the core. The most useful practical laminate for most purposes comprises a polystyrene core with a thin sheet of steel attached to each side by a bonding material.

A frame suitable for use with the laminate comprises extruded aluminum having a cross section resembling a truncated equilateral triangle with square shoulders at the base an gles. The frame can be fabricated from four straight frame members fitted together to form a rectangle with the truncated apex of the triangular cross section forming the interior surface of the triangle. The surface of the apex of the truncated triangular cross section forms a channeled receptacle into which the edge of the laminate fits. If the signboard is to have a shape other than rectangular, the sections of the frame will be shaped to fit around the edges of the laminate.

An important advantage of the magnetic signboard of this invention is its flexibility as to symbol size and weight so that the ideal sized symbol may be used for each selected use. A useful symbol according to the present invention comprises a surface to be displayed which has a usually perceptive depth rounded toward a back edge which is nearly coplanar with a flat magnetic material for' attaching the rear surface of the symbol to the ferromagnetic surface of the signboard. Accordingly, when a letter is placed on a signboard the rear edge is nearly flush to the ferromagnetic surface of the signboard.

The symbols may be fabricated from any material which is relatively strong, light in weight and. displays the required visual characteristics from its front surface in an attractive manner. Plastic having a color therein is useful for fabricating such symbols. Also, various coatings and paints may be used for selected purposes on the front'surface of each symbol to present a glow or fluorescent character thereto.

A magnetic sheet material is attached to the rear surface of each symbol at selected points which enable the surfaces of the ferromagnetic materials to support they symbol. Plastic struts or thin members can connect the magnetic sheet material to the back of the symbol. It is useful if the surface of the magnetic material and struts are slightly flexible, thereby providing an absorbent pad and damping any shock which may occur when a symbol is placed against the ferromagnetic surface of the signboard. The desired damping effect may be obtained by mounting the magnetic material on flexible V- or U-shaped struts.

BRIEF DESCRIPTION OF THE DRAWINGS Reference should be made to the detailed description herein which should be read in conjunction with the following figures of which:

FIG. 1 is an elevated plan view of a signboard according to the present invention;

FIG. 2 is a cutaway perspective view of a signboard according to the present invention;

FIG. 3 is a cross-sectional view of a laminate in part according to the present invention;

FIG. 4 is a cross-sectional view of a frame according to the present invention;

FIG. 5 is a bottomperspective view of a symbol according to the present invention; and

FIG. 6 is an end view of a symbol according to the present invention.

DETAILED DESCRIPTION FIG. 1 illustrates a plan view of a signboard 10. The signboard 10 comprises a frame 12 disposed around and supporting a laminate 14 including a ferromagnetic surface 16 to which symbols 18 are magnetically coupled. It should be noted that the symbols can be of any size, shape and orientation for placement on the ferromagnetic surface 16. In order to orient the symbols 18 on the board, and provide rigidity to the surface 16, ribs 19 are formed on the face thereof.

FIG. 2 illustrates the signboard in a perspective cutaway view disclosing the interior of the laminate 14 and cross section of the frame 12. The laminate 14 comprises a cellular core 20 having two ferromagnetic surfaces 16 and 22 affixed to the opposite sides thereof, with the aforementioned ribs 19.

FIG. 3 illustrates a cross-sectional view of the laminate 14. The laminate 14 includes a relatively thick core 20 which may be fabricated from a light, strong, solid material such as fiberglass, polystyrene, or honeycomb. Regardless of what the cellular core 20 is fabricated from, it should be of a high struc tural strength with relatively low weight. The preferred example herein comprises sheets of steel bonded to each side of the core20 with a bonding material 26 to form the ferromagnetic surfaces 16 and 22.

The ferromagnetic surfaces 16 and 22 may be fabricated alternatively by chemical deposition of ferromagnetic material from supersaturated solution, electroplating, spraying, or by any other means known to the art. For each of these possible means of applying the ferromagnetic surfaces 16, 22 to the core 20, the surface of the core 20 will, of course, have to be capable of receiving and holding the ferromagnetic material, Accordingly, certain of the above-listed means for applying a ferromagnetic surface can be applied only with certain types of core materials.

FIG. 4 illustrates the cross section of the preferred example of a frame for the present invention. The frame 12 has a cross section which resembles a truncated equilateral triangle with square shoulders 30 at the base angles. The edge of the laminate can be secured in a U-shaped channeled receptacle 7 31 having a width suitable for receiving, and a depth sufficient to securely hold the laminate 14. For each particular use, the U-shaped receptacle should have a depth sufficient to enable the frame to hold the laminate l4, and should also incorporate a base 34 of the U-shaped receptacle sufficiently wide to secure the edge of the laminate therein, in snug fitting relationship.

To avoid sharp edges and to give greater strength to the apex area of the cross-sectional triangle, the truncated portion of the triangle is formed with flat shoulders 36 parallel with the base rather than a sharp angle with the sides of the U- shaped receptacle.

The frame 12 has sides 38 formed as a portion ofa triangle, the shape of which should be governed by the well known laws relating to strength of materials. For some applications, the sides 38 may be curved concavely or convexly. The degree of the curvature of the sides 38 however, should also be determined at least in part by the required strength to hold the laminate 14.

A base 40 of the triangular frame is joined to the sides 38 by the two shoulders 30 rather than by the 60 angles normally joining the base and sides of an equilateral triangle. The shoulders 30 enable the frame to absorb stresses and shocks and avoid sharp angles which could injure persons working with the frame 12.

The frame 12 may be fabricated from various materials with internal braces extending across the frame or longitudinally along the frame. The preferred example of a frame 12 as described herein, is fabricated by extruding aluminum. The extrusion die forms longitudinal ribs 44 to strengthen the frame 12. To effectively brace the interior corners where the shoulders 30 connect with the walls 38, an interior angle rib 45 is also formed by the extrusion die.

FIG. 5 shows a perspective view of the symbol 18 which is an example of the symbols numerical, alphabetical or otherwise which may be utilized on the signboard hereof. The symbol 18 presents depth by means of a relatively flat front surface 48 curving backwardly at the edges to form sides generally perpendicular to the front surface which tenninate in a relatively planar rear edge 50. Various shapes of symbols may be used, and the shape of the front surface 48 and sides may be varied, and need not be planar. However, for best results, the rear edge 50 should be planar, so that it may be placed nearly flush to the planar surface 16 of the laminate 14.

FIGS. 5 and 6 show in detail the attachment means for the symbol 18. A rear surface 56 thereof is in effect a hollowed out image of the front surface 48. Struts 52 of a thin resilient material are attached to the rear surface at selected points. The struts 52 are provided with a relatively flat magnetic sheet 54 or pad. The struts 52 should be as thin and as light as possible as long as they are strong enough to support the symbol l8 and take whatever abuse may be given to them when they are placed against the sheets 16 and 22. The magnetic sheets 54 lie within a relatively coplanar surface with each other. The plane of the magnetic sheets 54 should be parallel to, and very slightly away from the rear of the plane of the rear edges 50 to insure that the magnetic sheets on the struts 52 contact the ferromagnetic surfaces 16 and 22 of the signboard 10.

As can be understood, the symbols 18 are placed against the signboard 10 in a relatively fast manner. Thus, many users are physically abusive in their handling or placement of the symbols 18. Therefore, the struts 52 should be slightly compressible and resilient to make it less likely that they will be broken by rough handling. The magnetic sheets 54 may also be somewhat compressible to act as a shock absorber for the struts 52 and the symbol 18. A useful magnetic material has been formed by embedding small increments of magnetic material in a flexible plastic base and utilizing the composite formed thereby as the sheet 54.

The invention has been described in detail to provide a full disclosure thereof as required under the patent laws. However, the detailed description is not intended in any way to limit the broad features or the scope of the invention as claimed, which is only to be read in light of the following claims.

We claim:

1. A signboard comprising in combination:

a laminate comprised of a relatively thick core of lightweight cellular material fixedly attached along at least one major surface to a relatively thin layer of ferromagnetic material;

a frame disposed around at least a portion of the edge region of said laminate, said frame being fabricated from an open extrusion of substantially triangular cross section having a portion thereof formed as an open substantially U-shaped channel for receiving the edge region of said laminate; and,

one or more magnetic symbols, each comprising a thin material having a portion suitable for a visual presentation and at least one thin and resilient strut affixed to the back of said symbol, each strut having a substantially flat magnetic material affixed thereto and wherein each of the flat portions of the magnetic material are substantially coplanar with each other.

2. A signboard according to claim 1 wherein:

said strut of said symbol is a thin flat strip of resilient material formed into a substantially U-shape, terminating in flanged end portions which are fixedly attached to the back of said symbol, and wherein said flat magnetic material is affixed to the cross member of said U-shaped strut.

3. A signboard according to claim 2 wherein:

said symbol is comprised of a hollowed out image having a relatively flat front surface curving backwardly at the edges to form sides substantially perpendicular to the front surface and terminating in a substantially planar rear edge, and wherein said magnetic sheets of said struts lie in a plane substantially parallel to said planar rear edge and extend beyond said rear edge.

4. A signboard according to claim 1 wherein:

said cellular core is polystyrene or a honeycomb material, said ferromagnetic material is a thin sheet of steel, and said frame is aluminum. 

2. A signboard according to claim 1 wherein: said strut of said symbol is a thin flat strip of resilient material formed into a substantially U-shape, terminating in flanged end portions which are fixedly attached to the back of said symbol, and wherein said flat magnetic material is affixed to the cross member of said U-shaped strut.
 3. A signboard according to claim 2 wherein: said symbol is comprised of a hollowed out image having a relatively flat front surface curving backwardly at the edges to form sides substantially perpendicular to the front surface and terminating in a substantially planar rear edge, and wherein said magnetic sheets of said struts lie in a plane substantially parallel to said planar rear edge and extend beyond said rear edge.
 4. A signboard according to claim 1 wherein: said cellular core is polystyrene or a honeycomb material, said ferromagnetic material is a thin sheet of steel, and said frame is aluminum. 